I never listen to talk radio, and I'm not sure whether or not I get those stations via the Dish.
All I can say is that the jazz station is excellent, and that I also get a second jazz station that's reserved for special events--concert broadcasts, etc.
There's also a station dedicated to swing, which I listen to on occasion, and there are two other jazz stations that are okay. One tends to get more fusion/new agey than I like, and the contemporary jazz station varies in quality (as does contemporary jazz). I suspect there are more jazz stations when you buy the fill Sirius line-up, which we haven't done. I think we get something like 100 channels now, but I've only added about 40 of them to my custom TV guide.
There are, however, no commercials. The DJs break in simply to say a few things about the songs after 5-6 have played, and since the DJs on the jazz station actually KNEW the people whose records they're spinning. So the DJ breaks are educational.
Oh, and occasionally an actual artist will join the DJ in the studio, which can be really interesting.